Whilst Out And About,

I often take a picture or two of the sky,

and comment something like, 'blue skies looking inland', or 'blue skies but with clouds coming in', or similar, but how blue is the sky? for the answer to that question I need a cyanometer, the simple device was invented in 1789 by Swiss physicist Horace-Bénédict de Saussure and German naturalist Alexander von Humboldt who used the circular array of 53 shaded sections in experiments above the skies over Geneva, Chamonix and Mont Blanc, but it was not only about the coulour, the cyanometer helped lead to a successful conclusion that the blueness of the sky is a measure of transparency caused by the amount of water vapor in the atmosphere, now where can I buy a cyanometer?